The present invention relates to a system for loading and unloading large volumes of liquid to and from a transport vehicle, such as an aircraft or ship transport.
A need has arisen for new and improved modes of transporting liquid fossil fuels from remote geographical regions where the fuels are found, to populated industrial areas of the world. The discovery and development of the northslope oil fields on the Alaskan and Canadian Arctic Rim, and other remote locations, has presented monumental problems in connection with the transportation of crude oil and natural gas to local refineries and storage facilities.
The northslope fields are situated in the furthest reaches of what could be regarded as one of the last land frontiers. There are no existing natural ports as such, and man-made ports are icebound for many months of the year. These ports are accessible only through the most determined icebreaking efforts, which for supertankers loaded with crude oil and holding the threat of massive pollution if the ships' hulls were damaged, is almost impossible to consider.
The weather is some of the most forbidding in the world, multiplying the difficult problems of on-loading crude oil and natural gas. Although an overland oil and gas pipeline may be one solution, a viable alternative thereto is needed.
As a result of the above obstacles, the use of gigantic aircraft transports with enormous liquid cargo carrying capacity, in the range of 2 million pounds, are envisioned. These aircraft could, for example, transport liquid natural gas from remote, isolated regions to local industrial areas for storage and subsequent use; a practice heretofore untried. However, in order to operate economically and transport sufficient volumes of liquid cargo, aircraft of the type and size described must be airborne almost around the clock, e.g., for 20 hours a day. This dictates that the liquid cargoes of these aircraft must be loaded on and off at heretofore unheard of transfer rates to keep the on-the-ground time at a very minimum.
However, existing valve and fluid coupling devices used to transfer massive volumes of liquid to and from storage tanks, sea-going freighters, pipelines, etc., are entirely inadequate to accommodate the required flow rates and are unadaptable to aircraft structural requirements.
For example, a coupling capable of accommodating the envisioned flow rates would have a cross-sectional flow area in the neighborhood of 30 square feet, allowing a flow of approximately 19,000 cubic feet per minute, a rate which will permit transfer of 2 million pounds (approximately 560,000 gallons) of liquid natural gas, in approximately 4 minutes.
Additionally, the large volume, high rate transfer of cryogenic liquid natural gasses will inherently involve extreme temperature cycling of the components of the transfer apparatus. No known fluid coupling devices are capable of satisfactorily operating under these extreme temperature conditions and yet, at the same time, accommodating the large flow rates of liquid.
Furthermore, while the special requirements of aircraft transports provide an important example of the need for new liquid cargo loading and unloading devices, other transportation and storage modes can benefit from improved loading and unloading systems. The transfer of large volume liquid cargoes to and from sea-going freighters or ship transports, such as liquid natural gas tankers, will be significantly improved by providing equipment for increasing the flow rate of the liquid cargo during loading and unloading. Indeed, the transfer of liquid to or from any transport vehicle or carrier, whether a land, sea, air or space transport may be enhanced by providing apparatus for increasing the rate of liquid flow during the transfer operation.